This invention relates to double ported valves, and in particular, to a double ported valve finding application as a thermostatic controlled expansion valve in a refrigeration system. While the valve is described with particular emphasis to its use as an expansion valve, those skilled in the art will recognize the wider applicability of the inventive principles disclosed hereinafter.
Double ported valves frequently are used in refrigeration systems where capacity requirements of the systems exceed that which can be controlled by a valve with a single valve port. The thermostatically controlled valve is positioned in the refrigeration system to control system operation by modulating the amount of refrigerant passing through the valve restriction. That is, refrigeration systems generally include an evaporator, a compressor and a condenser. Refrigerant vapors drawn from the evaporator by the compressor are forced into the condenser, where the vapor liquifies. The liquid refrigerant then is returned to the evaporator through an expansion valve. Control of refrigerant input to the evaporator can be maintained by inserting a valve member in the restriction of the expansion valve and adjusting the valve member in response to a particular sensed condition. The modulating means often includes a temperature sensing diaphragm actuated valve member. The sensor is connected to one side of the diaphragm, while a spring is biased between the valve and the diaphragm on a second side of the diaphragm.
The prior art reveals a number of double ported valves useful in conjunction with refrigeration applications constructed in accordance with the general outline described above. For the most part, these valves have used a construction which requires gasketed joints at the interconnection of the thermostatic control element and the valve body. One disadvantage with a gasketed joint type construction is that such construction requires close tolerance control, resulting in high manufacturing costs. In addition, in field use, the gasketed joint is not as reliable as a welded, soldered, brazed or similar permanent connection, for example, in that gasket wear can affect valve operation adversely. Another disadvantage with prior art valves is that the spring used in connection with the thermostatic control often is placed adjacent the diaphragm, a valve stem of the valve passing through the spring to an operating interconnection with the diaphragm. With double ported valves, such an arrangement requires relatively complex means for sealing the valve stem against leakage, particularly if adjustment of the force exerted by the spring is a valve feature.
The invention described hereinafter overcomes these prior art deficiencies by providing a double ported valve arranged so that the valve may utilize an integrally constructed valve body. The valve body generally takes the form of an open ended cylindrical tube having an inlet and an outlet passing radially through the valve body. The thermostatic control device is mounted to one end of the valve body, while an adjustment means is mounted to the other end of the valve body. Because of the oppositely opposed relationship of the adjustment means and the thermostatic control means, a relatively short stroke valve design is possible, which permits a reduction in the amount of packing required to seal the valve stem against leakage.
One of the objects of this invention is to provide a double ported thermostatic controlled expansion valve having an integral valve body.
Another object of this invention is to provide a thermostatically controlled double ported valve with an integral valve body having the thermostatic control meand positioned on a first end of the valve body, and an adjustment means positioned on a second end of the valve body.
Another object of this invention is to provide a short stroke double ported thermostatically controlled valve.
Still another object of this invention is to provide a low cost, double ported valve.
Other objects of this invention will be apparent to those skilled in the art in light of the following description and accompanying drawings.